System for amplifying electric waves.



H. GOLPITTS. SYSTEM FOR AMPLIFYING ELECTRIC WAVES.

APPLICATION FILED APR. 6, 1914.

Patentd Mar. 2,1915.

' menace.

- To all whom it may concern EDWIN H. COLPITTS, OF EAST ORANGE, NEW JERSEY, ASSIGNOR 'IO WESTERN ELECTRIC COMPANY, OF NEW YORK, N. Y., A CORPORATION OF ILLINOIS.

. SYSTEM FOR AMPLIFYING ELECTRIC WAVES.

Application filed April. 1914. Serial No. 829,997.

Be it known that I, EDWIN H. CoLrn'rs, a subject of the King of Great Britain, residing at East Orange, in the county of Essex and State of New Jersey, have invented a certain new and useful Improvement in Systems for Amplifying Electric Waves, of which the followin is a full, clear, concise, and exact description. i a

This invention relates to electric signaling, and particularly to signaling. over ocean cables. v

-()ne of its objects is to amplify eficiently very feeble low frequency electric waves.

A special object is to provide an efficient amplifying system adapted without transformers for use at the receiving end of a signaling circuit. a

A well known law of electric circuits requires that the impedance of the external path in the circuit should be equal to the impedance of the internal path or source, whenever the maximum of available energy is desired. In ocean cable telegraphy it is usual to connect a siphon recorder directly to the land terminals of the' cable circuit. In order, therefore, to utilize in the recorder the maximum energy obtainable, the receiving magnet of the recorder should be wound to offer an impedance of the same order of magnitude as that of the cable circuit measured at. its incoming terminals. For example, if the. impedance of the cable circuit measured at its incoming terminals to currents at telegraphic frequency is say, 2000 ohms, the best impedance for the recorder magnet would in this case also be 2000 ohms. When such an equalization of impedances is secured, the circuit may be saidto be balanced. But, if the impedances of the source and of, the receiving device are greatly out of proportion, there is an unbalanced conditionand a loss of available energy.

Of the various types of known amplifying devices, those in the general class of vacuum discharge repeaters such asthe ionized gas type and the type known as thermionic exemplified by the 'audion have advantages with respect to amplifying very low frequency currents, since the output currents in such devices are not subject to severe distortion due to external or internal disturbances, but aresubstantially determined as to their form by the form of the input current.

similar high impedance.

Furthermore, ionized gas repeaters of the species which make use of electromagnets for receiving incoming currents, may readily have their magnets wound to approximately the impedance of cable circuits so that they may be operated efficiently, I when directl connected to the incoming terminals of suc circuits. Also as to audions, it is noted that theimpedance of their output circuits, althrough considerably higher than that of the ordinary siphon recorder used in ocean cable telegraphy is not usually so high as that of their input circuits and may, by suitable arrangements, be rendered still lower, thereby adapting the audions for direct connection to recorders. One way of lowering the output impedance is to employ a plurality of audions having their output c1rcuits connected in parallel. In this way the impedance may be reduced sufficiently to form fairly well balanced connections with recorders. The ionized gas repeater, however, has an output circuit of the order of several hundred thousand ohms impedance, while the audion has an input circuit of Such impedances' are so out of proportion to that of a cable circuit or that of any practical winding for a siphon recorder, that a direct connection between the output terminals of the gaseous repeater and a siphon recorder, or one be-- tween the input terminals of an audion or even a bank of audions in multiple and a cable circuit would result in ineiiicient operation. Furthermore, on account of the very low frequency of the minuteelectric waves in cable telegraphy, these waves in certain cases as in ocean telegraphy being as low as Specification 01' Letters lPatent. 'lPat'itentetll Mar. 2, liti llfio.

two periods per second, it is extremely desirable to avoid the use of a transformer,

the design of which for use in conjunction with vacuum discharge repeaters, such as ionized gas or thermionic repeaters or the like, between the cable and the recorder would be a very difiicult matter.

-The unbalanced condition and ineflicient operation'which would be met in the use without a transformer of any known type of vacuum discharge repeater and the necessity of using the undesirable transformer to balance impedances are at once avoided in Y accordance with this invention by the use'of two or more vacuum discharge repeaters:

and Working one into the otherby direct" having different impedance characte'ristic'sa connection. Two such vacuum discharge repeateiis may be placed in seriatz'm between the cable and receiver, the one connected repeater, and the one or more connected witlr the receiver having hrgh input impedance such as the audion, and preferably arranged to offer a comparatively low output impedance. The output-input circuit between two such amphfying repeaters placed in this relation including as it does high impedance pathsin both, is electrically balanced and the system as a whole is well adapted for eificient amplification. Naturally the voltage and current characteristics of this high impedance output-input circuit are such that the voltage changes are high and the current changes low in comparison with the voltage and current changes in the input circuit of the first repeater.

A. system embodying the invention will be described more in detail in the following specification together with the accompanyinig drawings in Which Figure 1 is a diagram of circuits as applied to an ocean cable and a recorder; and Fig. 2 is a diagram showing the application of the invention to the juncture of two cable sections where the eurrentsreceived from one section are repeated in the other.

Referring to Fig. 1, the circuit of an ocean cable is represented by conductors l and 2 leading to an ionized gas repeater 3 and connected directly in circuit with an electro-magnet 4 thereof. A receiving device 5, which may be a siphon recorder, is

- provided for reproducing or recording the electric waves received through the cable.

Between the repeater 3 and recorder 5 are connected a plurality of repeaters of the audion type 6, 7, 8 and 9. The output circuit of the gaseous repeater 3 is connected with the input circuit of each of the audions 6 to 9, the complete circuit being as follows: from the filaments 11, 12, 13 and 14 of the audions, through conductors 15 and 16 to an electrode 17; thencev through the ionized gas in the repeater to another electrode 18, and through conductors 19 and 21, battery 22, grid 23 of audion 6, and the space between the grid and filament. Parallel paths lead through the grids and spaces in each of the audions. Batteries 24, 25 and 26 are included in extensions of" the conductor 21 in order to equalize approximately the normal potential differences between the grids and filaments in the several audions, it being noted that the filaments are connected in series and fed byv a battery 27, the circuit of which includes a resistance 28 to regulate the flow of current. The several plates 33, 34, 35 and 36 of the audions are connected in multiple circuit with the receiving device 5, the circuit being traced as follows: from the filaments 11, 12, 13 and 14, through conductor 37, battery 38, conductor 39, receiver 5, conductor 41, condenser 42 and conductor 43 to the several plates 33 to 36 thence in parallel through the spaces between the plates and filaments in each audion. Connected across this circuit is an impedance device 44, the coil of which serves as the path for a normal flow of direct current from the battery 38 to the several audions. This device is of high impedance so as to avoid shunting the varying currents generated in the output circuit of the audion-s.

A normal flow of current to the gaseous repeater 3 is supplied by battery 45, one pole ()11Whl0l1 is connected to an anode 46 and the other of which is connected through a regulating resistance 47 and conductor 48 to a cathode 49. This cathode 49, in the preferred form of the deyice, is of mercury and an arc is formed between the cathode 49 and the anode 46 which completes the circuit of battery 45 and causes the formation of an ionized gas (mercury) in the vessel 51. This gas renders the space conductive between the electrodes 17 and 18 and the anode 46. A normal flow of current is provided in the output circuit of the repeater 3 also from the same battery 45, the circuit extending from the negative pole of the battery 45, through the resistance 47 to conductor 52, where the circuit divides, one branch leading through impedance coil 53, eonductor'16, the electrode 17, and that part of the ionized gas which lies between this electrode and the anode 46, to the positive pole of batte 45. The other branch may be traced similarly through the impedance coil 55, conductor 19, the electrode 18, and that part of the ionized gas which lies between the electrode 18 and the anode 46.

The operation is as follows: The feeble currents of low frequency received in the input circuit" from the cable circuit conductors 1, 2 produce, by means of the electromagnet '4, a fluctuating magnetic field and a corresponding varying deflection of the gaseous ions to the right and left in the region of the electrodes 17, 18. This causes a corresponding varying flow of current of amplified energy in the conductors 16 and 19 and therefore in the output-input circuit between the gaseous repeater 3 and the audions 6 to 9. These audions, each of which receives a part of the energy of this current, reproduce the waves of current with amplified energy in the output circuit leading to they receiver 5. The dillerent parts of these circuits are or may be balanced electrically in the following manner: The electromagnet 4 of the gaseous repeater 3 may be wound to any impedance desired, thus making it of an impedance of the same order of magnitude as the cable from which it 73 of the other cable conductor 62. This receives energy. By using a number of audions in the way shown in Fig. 1, the combined impedance of the output circu1t may be made of the same order of magnitude as the receiver or siphon recorder. The output-input circuit between the gaseous repeater 3 and the audions is naturally well balanced, inasmuch as the output circuit of the. gaseous repeater and the input circuit of the audions are both of high impedance and approximately of the same order of magnitude.

In Fig. 2,61 and 62 are conductors of different cables which may terminate at the same landing point and form sections of a common circuit. Where two-way trans mission or duplex operation is desired in such a circuit, an artificial line, such as the lines63 and 64, are provided for each conductor. Each such artificial line may comprise .a resistance 65, and distributed capacity between this resistance and a ground plate 66. The cable conductor and itsartificial line are joined by two condensers of large capacity 68 and 69, and at the junction point between these condensers a conductor 71 leads through suitable apparatus to ground. In applying this invention to the repeating of currents from one such cable conductor to the other, the input 'cir-.

cuit (conductors 1 and 2) of a repeater set 60, like that of Fig. 1, may be connected in bridge between the cable conductor 61 and its artificial line 63, and a condenser 72 may be inserted in this bridge, while the output circuit (conductors 39 and 41) of the set may be connected in the ground conductor provides for signaling from conductor 61 to conductor 62. For signaling in the opposite direction the arrangement is exactly similar. As shown, the input circuit (conductors 1 and 2) of a second repeater set 74, also like that of Fig. 1, is connected in bridge of the cable conductor 62 and its artificial line-64:, while the output circuit (conductors .39, 41) in the ground conductor 71. By this arrangeriient messages may be transmitted in both directions simultaneously through circuit of the cable conductors 61 and 62, and the currents amplified at. the

, point where the sections are united.

What is claimed is:

1. The combination with a low impedance source of varying currents and a receiver adapted to respond to such currents, of an amplifying repeater connected with said source and having an output circuit of high impedance compared to said source, and a second amplifying repeater connected between s aid first repeater and said receiver and having aninput circuit also of. high impedance compared to said source.

2. The combmation wlth a source of varyof the set is connected in the ing currents and a receiver adapted to respond to such currents of an ionized gas repeater having an inputelectromagnet connected to said. source and an output circuit including a path through the gas of said repeater, and an audion repeater connected with its input circuit in series with the output circuit of said gas-repeater and its output circuit connected to said receiver.

3. The combination with a-cable' circuit and a receiver adapted to respond to electric waves in said circuit, of two amplifying repeaters connected in seriatim between said cable and said receiver, the output-input circuit between'said repeaters being of high impedance compared to said cable and to said receiver.

4. y The combination with asource of-feeble electric waves of low frequency and a receiver adapted to respond to said waves, of two amplifying repeaters connected in 86- 'ra'atim between said source and said receiver,

oneof said repeaters having an input circuit directly connected with and of impedance of the same order of magnitude as said source, the other" of said repeaters having an output circuit connected with said receiver, and a circuit joiningsaid repeaters having paths in each of high impedance compared to said source.

5. The combination with a cable circuit and a receiver adapted to respond to electric waves in said circuit, of an ionized gas repeater having an input electromagnet connected to said cable, a plurality of audion repeaters, the output circuits of which are connected in parallel with each other and in circuit with said receiver, and an output-- input circuit including paths through the gas in said first-mentioned repeater and through said audion repeaters.

6. In an amplifying system, the combi nation of two vacuum discharge repeaters having different impedance characteristics and a connection between them whereby one works directly into the other.

In an amplifying system, the combination with an ionized gas repeater and a thermionic repeater, of a connection between them .whereby said ionized gas repeater lit works directly into said thermionic repeater.

having a high output impedance, and a second vacuum discharge repeater into which said first mentioned'repeater works, saidI 10 peaters.

12. The combination of a line of low impedance of; amplifying repeater having its input circuit directly connected to said line, and a second amplifying repeater into 15 which said first mentioned repeater works the output-input circuit between said 'repeaters includinghigh impedance paths in;

each re eater.

set of repeaters directly connected in seriat-im between said lines, the output-in ut circuit between said repeaters being of high impedancewith respect to said lines.

In witness whereof, I hereunto subscribe my name this 3rd day of April A. D.,- 1914. EDWIN H. COLPITTS.

? Witnesses: v

KATHERINE L. STAHL, NORAH E. TUTHILL.

he combination with an incoming and an outgoing line of-lowimpedance, of a- 

